Re: [PATCH 08/16] media: i2c: ov9282: Add selection for CSI2 clock mode

[Sakari Ailus <sakari.ailus@iki.fi>]

Hi Dave,

On Wed, Oct 05, 2022 at 04:28:01PM +0100, Dave Stevenson wrote:
> The sensor supports either having the CSI2 clock lane free
> running, or gated when there is no packet to transmit.
> The driver only selected gated (non-continuous) clock mode.
> 
> Add code to allow fwnode to configure whether the clock is
> gated or free running.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> ---
>  drivers/media/i2c/ov9282.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> index abb1223c0260..334b31af34a4 100644
> --- a/drivers/media/i2c/ov9282.c
> +++ b/drivers/media/i2c/ov9282.c
> @@ -46,6 +46,9 @@
>  /* Group hold register */
>  #define OV9282_REG_HOLD		0x3308
>  
> +#define OV9282_REG_MIPI_CTRL00	0x4800
> +#define OV9282_GATED_CLOCK	BIT(5)
> +
>  /* Input clock rate */
>  #define OV9282_INCLK_RATE	24000000
>  
> @@ -138,6 +141,7 @@ struct ov9282 {
>  	struct clk *inclk;
>  	struct regulator_bulk_data supplies[OV9282_NUM_SUPPLIES];
>  	struct v4l2_ctrl_handler ctrl_handler;
> +	bool noncontinuous_clock;
>  	struct v4l2_ctrl *link_freq_ctrl;
>  	struct v4l2_ctrl *hblank_ctrl;
>  	struct v4l2_ctrl *vblank_ctrl;
> @@ -211,7 +215,6 @@ static const struct ov9282_reg common_regs[] = {
>  	{0x4601, 0x04},
>  	{0x470f, 0x00},
>  	{0x4f07, 0x00},
> -	{0x4800, 0x20},
>  	{0x5000, 0x9f},
>  	{0x5001, 0x00},
>  	{0x5e00, 0x00},
> @@ -684,6 +687,14 @@ static int ov9282_start_streaming(struct ov9282 *ov9282)
>  		return ret;
>  	}
>  
> +	ret = ov9282_write_reg(ov9282, OV9282_REG_MIPI_CTRL00, 1,
> +			       ov9282->noncontinuous_clock ?
> +					OV9282_GATED_CLOCK : 0);

Wouldn't this better fit for power on?

> +	if (ret) {
> +		dev_err(ov9282->dev, "fail to write MIPI_CTRL00");
> +		return ret;
> +	}
> +
>  	/* Write sensor mode registers */
>  	reg_list = &ov9282->cur_mode->reg_list;
>  	ret = ov9282_write_regs(ov9282, reg_list->regs, reg_list->num_of_regs);
> @@ -861,6 +872,9 @@ static int ov9282_parse_hw_config(struct ov9282 *ov9282)
>  	if (ret)
>  		return ret;
>  
> +	ov9282->noncontinuous_clock =
> +		bus_cfg.bus.mipi_csi2.flags & V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
> +
>  	if (bus_cfg.bus.mipi_csi2.num_data_lanes != OV9282_NUM_DATA_LANES) {
>  		dev_err(ov9282->dev,
>  			"number of CSI2 data lanes %d is not supported",

-- 
Kind regards,

Sakari Ailus